Polycrystalline diamond for drawing dies and method for fabricating the same

Abstract

Provided are polycrystalline diamond for drawing dies, which inhibits preferential wear along specific lattice planes while ensuring wear resistance by controlling the shape and orientation of the grains forming polycrystalline diamond solid, and a method for fabricating the same. The polycrystalline diamond for drawing dies includes a section of diamond having an isotropic granular structure or a radially oriented texture, or has a stacked structure including an isotropic granular layer and a radial texture layer alternately in multiple layers.

What is claimed is: 
     
         1 . Polycrystalline diamond for drawing dies, comprising a section of diamond crystalline texture having radially elongated columnar grains. 
     
     
         2 . Polycrystalline diamond for drawing dies, comprising an isotropic equiaxed grain layer and a radially elongated columnar grain textured layer, stacked alternately in multiple layers. 
     
     
         3 . A method for fabricating polycrystalline diamond for drawing dies, comprising carrying out a chemical vapor deposition (CVD) process using hydrogen (H 2 ) and methane (CH 4 ) as precursors to form polycrystalline diamond having isotropic equiaxed grains on a substrate, wherein methane is present at 4-5 vol % in the mixed gas of hydrogen (H 2 ) and methane (CH 4 ). 
     
     
         4 . A method for fabricating polycrystalline diamond for drawing dies, comprising carrying out a chemical vapor deposition (CVD) process using hydrogen (H 2 ) and methane (CH 4 ) as precursors to form polycrystalline diamond solid having radially elongated columnar grains on a substrate, wherein methane is present at 1-2 vol % in the mixed gas of hydrogen (H 2 ) and methane (CH 4 ). 
     
     
         5 . The method for fabricating polycrystalline diamond for drawing dies according to  claim 3 , wherein the substrate has a temperature of 700-950° C. 
     
     
         6 . The method for fabricating polycrystalline diamond for drawing dies according to  claim 4 , wherein the substrate has a temperature of 700-950° C. 
     
     
         7 . The method for fabricating polycrystalline diamond for drawing dies according to  claim 4 , wherein the diamond solid having the radially elongated columnar grains is grown by using a chemical vapor deposition (CVD) process, while diamond powder is distributed randomly and individually on the substrate. 
     
     
         8 . The method for fabricating polycrystalline diamond for drawing dies according to  claim 4 , wherein the diamond solid having the radially elongated columnar grains is grown by using a chemical vapor deposition (CVD) process, while the substrate surface is subjected to specific pretreatment for diamond nucleation. 
     
     
         9 . A method for fabricating diamond for drawing dies, comprising:
 stacking isotropic equiaxed grains diamond crystal layers and radially elongated columnar grains textured diamond crystal layers alternately in multiple layers on a substrate by a chemical vapor deposition (CVD) process using hydrogen (H 2 ) and methane (CH 4 ) as precursors,   wherein methane is present at 4-5 vol % in the mixed gas of hydrogen (H 2 ) and methane (CH 4 ) upon forming the isotropic equiaxed grains diamond crystal layers, while methane is present at 1-2 vol % in the mixed gas of hydrogen (H 2 ) and methane (CH 4 ) upon forming the radially elongated columnar grains textured diamond crystal layers.   
     
     
         10 . The method for fabricating polycrystalline diamond for drawing dies according to  claim 9 , wherein the substrate has a temperature of 700-950° C.